Wireless train control



Dec. 30, 1930., .1. H. HAMMOND. JR 1,786,610

WIRELESS TRAIN CONTROL Filed Aug. 1'7 1922 www @alienated .lilly l conn nef-rs wenn, an, or ononcnsrnn, nnsseonnsnrrs Application fil-ell iaugust i?, 11322. Serial Elo,

This invention relates to improvements in systems of train control and more particularly to a system oi signalling `for the control of a train employing radiant energy or so- 5 called Hertzien Wares.

ln its broader aspect the yinvention corn-= prises a system ont guided Wave radio signalling whereby the engineer or othereoperator of the train may be yroede aware ci condi- 19 tions in advance of the train, so thatftlie train need not be placed in jeopardy by approaching too closely to another train in ad- Vance thereof.

More particularly, the invention comprises a sending station or Atransnriitter positioned in one portion of a train and adapted to emit' radiant oscillations or so-called Hertzien Waves; a receiving station positioned in another portion ot the train, responsive to the oscillations emitted by the sending station; Iand a stationary rneans on tire roadbed torniing a loop which seri/'es as a guide 'for the radiant oscillations between the sending station and the receiving station one given train and which may have its electrical characteristics or constants varied by means of a signal relay.

ln the present application the terni train is intended to include a single movable body which maybe articulated in a well known manner so as to go around curves or 'which may comprise a line oi vehicles drawn by an engine or other self propelled `vehicle, as is customary in the `railroad art.

The signal relay referred to is employed inthe prior v4art to control semaphore bloclr signals and isitself `controlled in a Well known manner by train conditions existing in the two blocks in advance of 'the sema- 39 phore signals controlled thereby0 ln the prior art it is usual to employ for this purpose a polarized relay Whose armature is operated in one direction when there are no trains in the two blocks mentioned, at which 5 time a clear signal is indicated by the sernaphores; and in the other direction when there is a train in the second block in advance at which time a cautionsignal is displayed by the semapliores `The. relay is entirely dei energized when there is a train in the next block in adi/ance, the` winding ot the relay being short circuited by the Wheels and arles oie the train.

in the practice ofthe present invention a loop ,is provided extending substantially the length of each block. This Aloop may be formed of a conductor extendingl substantially the length of each bloclr which, in combination with one of the track relays of the roadbed, to which it is connected at one end of the block, forms e closed oscillatory circuit or loop. The sinal relay referred to above and controlled by traiic conditions in the blocksl in advance of the respective block is arranged to control a desired one oi the electrical constants of the loop. For example, the inductance of the loopmay be varied in the diierent positions oi the relay armature or the capacitance characteristic may be Varied thereby. Either or both ci the characteristics of the loop may be Varied in the manner described according to train trac conditions in advance of the respective bloeit,

and the frequency ci oscillations to "which the loop will resonate most easily may be Varied accordingly.

,el sending station is provided on each train which is to be protected by the system oi the present invention. The sending station is preferably positioned in a portion of the 'train remote from the engineer or other 'person to Whom the indications are to be given. Usually the sending station is to be positioned at the rear end of the train9 but it 'the train happens to be longer than any bloclr, it will be necessary to position the sending station in seine portion ci the train spaced apart from the observer by a distance less than the length of a bloclr.

el receiving station is provided preferably near the engineer or operator of the train, and is so controlled by the sending station in combination with the loop that varying char- -acteristics'oi 'the loop will modify 'the signals in the receiving station according to the road trac conditions.,

Since a block is always longer than the distance between the sending station and receiving station ci a train, the high frequency oscillations emitted by 'the sender will canso diately in advance, in which case the signal relay winding will be short circuited andthe amature thereof will be in neutral position and little or no response wiil be given bythe receiving station or whether there is a'. train only in the second block in advance, in which case a diierent quality of response will be given by the receiving station; or Twhether there is no train in the next block in advance in which case a third quality of response. will be given.

In the drawing there is shown one embodiment of the invention in which the railroad road-.bed is divided into blocks, and a train provided with a sending station. and a receiving station.

Figure l shows my important wireless train control system.

Figure 2 shows one type of biock relay control circuit.

Referring to the drawing, a train l0, which may comprise an engine 1l, and trailing bodies 12, 13, 14, is provided with a sendmg station 15 positioned in one of the trailing bodies, such as the body 14, for example. The train .is shown in diagrammatic form, the forward wheels and axles and 'the rear wheels and axles thereo being shown separated therefrom for the purpose of more clearly illustrating the :features or the in.- vention. lt is understood, however, 'that ail of the train wheels co-operate in the same manner with the roadbed. 'Ehe sending station l5, which is adapted. 'to high `irequency radiant oscillations, includes a loop 18 carried by the respective body in a posipi immediately above the ievef. ci the road- Similarly, the engine il is provided with a receiving station 16 which includes loop 17 carried immediately abovethe ievel ot the roadbed.

The roadbed comprises a pair ci' track rails 20, 21 of conventional torni upon which the train wheels move. The rcadbed is divided by insulated iish plates `not shown) into a plurality of successive blocks such as 22, 23, 24. Each of these blocks is provided at or near the point at Whicha train normally enters with a signal relay 25 which may take the form of a polarized direct current relay operated by the so-cailed track current. The control of such track signal relays is weil known in the art and a detailed description thereof is unnecesary in the present application.

As is well known, lit is customary to cause the movement of the armature of such a signal' relay in one direction, for example, to close contact 26, when there is no train in eitherl the block to which the relay winding is' connected, or in the block in advance thereof. When, however, there is a trainl in the block in advance thereof but no train in the block to which the relay winding is connected, in the present instance the block `designated 24, the direction ofcurrent through the winding is reversed and the relay armature is caused totake up an opposite osition, for example, to close Contact 27 ever, there is a train'in the block to which the. relay winding is connected, in the present instance block 24, the relay is shortcircuited and its armature takes a neutral position, as for example, that shown in the drawing. ltV is understood that the relay armature may control terminals, in addition to those shown, for closing the circuits governing the action of the usual semaphore signals placed near the entrance of the block to which the relay Winding is connected, in a Well known manner, as illustra-ted in Figure 2.

Thus as the train enters block B the mag net of relay A, is short circuitedand the armature assumes the neutral position and when. the train leaves this block and enters block C the armature of relay B1 is moved into neutral position causing the reversal of the current flowing through the rails of block and the magnet of relay A1 and causing the armature of said relay to assume the, upper position closing contact 26. When the armature of relay Bl is caused to go to the upper position by the train entering the next block D (not shown), the current fiowing 'through the rails of block l5 is again reversed as may be seen from the diagram and the armature of relay A, is moved to the lower position. closing contact 27 of Fig. 1. Thus each relay armature in addition makes the contacts'v necessary to change the characteristics of the signaling loop as illustrated in F ig. l. lt to be understood that any appropriate means may be used to operate the relay, that shown being merely for purpose of illustration and forming no part of the present invention per se.

Each block islprovided with a conductor 30 extending substantially the length thereof, which in combination With one of the track rails 21 or with a separate conductor,`

forms a loop or closed oscillatory circuit for the respective block. This loop acts as a guide for the electro-magnetic waves emitted by the sending station l5, to control the receiving station 16. The loop so formed may also include one of the condensers 31 or 32 eol 7hen, hoW- arenoso according to the position of the armature oi" the relay 25 and thus the' electrical lconstants of the loop, and .the frequency to which the closed oscillatory circuit formed thereby will most easily resonate, may be varied.

t is understood that the lapparatus shown for each block may he duplicated ffor they other hlochs of the roadhed. y

ln the operation of the' system of the present invention the sender l through its loop 18 emits oscillations which cause oscillatory electro-motive forces to he set up in the loop including the conductor 30. y

lt will iirst be assumed that there is a train in the next block Qt in advance ofthe train lll, so that the Winding of the relay will be snort circuited and the armature thereof will be in the neutral position as shown inv the dravving. Little or no current will therefore dow in the loop including the conductor and there Will he little or no response in the receiving system 16. he engineer Will therefore he warned of danger and will bring his train to a stop.

if, however, there is no train in the hloch 2d, but there is a train inthe hloclr in advance thereol, that is to say, conditions prevail which require caution on the part ci the engineer of the train lll, the relay 25 will he operated in a direction to close the contact 26z rl`he condenser 3l Will then be included in the circuit of: the loop associated with oloclr 23. rlChe condenser 3l is ot such capacity that a limited oscillatory current or one ot i predetermined frequency will he permitted to iiow in the associated loop, and thus a response oi a predetermined and easily recognised character will he produced hy the receiver le. rllhe oscillations inthe loop are forced oscillations. li, however, there is no train in either ot the tivo blocks in advance of the train l0 the relay 25 will he operated in such a direction as to close the circuit to coni tact 27 and the condenser 82 will he connected in the circuit of the loop of the block-23.

llhe condenser 32 is of such capacity as to nroduce a diderent response in the loop to the oscillations impressed thereon hy the loop i8. rlhere will thus he produced in the loop il carried hy the engine il electro-motive forces ot corresponding character and the receiving station 1 6 will he actuated to produce a signal indicating that conditions ahead are clear, and that the engineer may proceed.

rlhus it will he seen that l have provided a system, in which both. the sending station and receiving station involved in producing a: signal are positioned on the same train, therehy rendering it possible to maintain the system in good working orderwith a minimum of expense. Furthermore, the loops i8 and l? carried hy the train may he spaced apart i'rom the conductor 30 and thus the need for auxiliary contact shoes or other contact malrf ing devices is ohviated.,

The sending and' receiving stations are shielded from direct action on each other by shields such as grids or gauze sheets 4C() and il respectively, grounded to a convenient truck axle as shown.

The system of my invention provides a signal for the engineer of the train so long vas clear conditions prevail, and when conditions requiring caution or danger conditions occur the signal will be reduced or eliminated. 'lhus failure ofthe sending station will tend to cause the engineer to exercise caution and such failure will not put the train in jeopardy. lt Will also he seen that the system may be readily employed in conjunction with ordinary hlocksignalling systems of the prior art Without interfering with or, modifying the operation thereof.

illustrative apparatus has been shown for the purpose of specifying one Way in which the invention may be practiced,vhut it is expressly understood that the scope of the invention is not to be limited'therehy, reference being had to the appended claims for that purpose.

'What is claimed is:

l. ln a train control system, a train having a sender near one end for emitting high frequency waves, and a receiver near the other end i'or receiving the high frequency Waves, a roadhed for the train divided into blocks, guiding means lor the `high frequency waves extending along substantially the length of each bloeit, and means controlled hy train trame conditions in hloclrsin advance of a given block to vary the electrical constants of the respective guiding means.

kln a train control system the combination with a road bed having an electrical circuit extending longitudinally thereof, a polarized relay arranged to vary the electrical condition of said circuit from a normal condition to any one oi a plurality of other conditions as a result oi trailic conditions along said road hed, means carried hy a train for producing electricaloscillations in said circuit, and telephonie receiving means carried hy said train and arranged to he controlled as a result of the action oi said oscillations in said circuit.

d ln comhination, a train, a continuous conductive loop circuit, a radio frequency sending loop attached to the train, and a radio rrequency receiving loop attached to the train and cooperating with the loop circuit.

Il. ln comhination, a train, a loop circuit having means for changing its characteristics included therein, a sending loop and alreceiving loop hoth attached to the train and "shielding means between said loops.

5. ln combination, a train, a radio frequency sending loop attached to the train, a radio frequency receiving loop attached to the train some distance 'from the sending loop and means vvherehy the oscillations prolll@ duced by the sending loop are received in the receiving loop, the` radio frequency characteristics of said means being controlled by a tratlic regulating arrangement.

6. In combination, a train, a sending loop attached to the train, a receiving loop attached to the train some distance from the sending loop and conductive means whereby the oscillations produced by the sending loop are received in the receiving loop, said means being controlled by a trallic regulating arrangement for changing the radio frequency characteristics of the conductive means for different conditions of traffic.

7. Means for controlling traiic consisting of a series of blocks, radiant energy conductive means extending over each block, radiant energy sending means on a tratiic element, and radiant energy receiving means on the element whei'eby the condition of traffic is indicated by the type of transmission vobtained between the sendingmeans and the receiving means.

8. Means for controlling traliic consisting of a series of blocks, radiant energy conductive means extending over each block, radiant energy sending means on a traiiic element, and radiant energy receiving means on the element, whereby the condition or trafiic is indicated by the type of ltransmission obtained between the sending means and the receiving means over the radiant energy responsive means.

9. Means for controlling tra-flic consisting of a series of blocks, variable radiant energy conductive means extending over each block, radiant energy sending means on a tradic element, and radiant energy receiving means on the `element, whereby the condition oic traffic is indicated by the type of transmission obtained between the sending means and the receiving means.

10. Means for controlling traiiic consisting of a series of blocks, variable radiant energy conductive means extending over each bioclr, radiant energy sending means on a traiiic element, and radiant energy receiving means on the element, whereby the condition oi: traiic is indica-ted by the type of transmission obtained between the sending means and the receiving means over the radiant energy responsive means.

11. Means for controlling traffic consisting of a series of blocks, variable radiant energy conductive means extending over each bloclr, radiant energy sending means on a traffic ele* nient, and radiant energy receiving means on the element, and means to vary the characteristics of the responsive means to any one of several stages according to the traiiic condition.

12. Meansfor controlling traiiic consisting of a series of blocks, variable radiant energy conductive means extending over each block, radiant energy sending means on a trame element, and radiant energy receivingnieans on the element, and means to vary the characteristics of the responsive means to any one of three stages according to the traii'ic conditions.

13. In combination, movable members and stationary means, several radio frequency' wave devices attached to 'the movable members'for cooperating with conductive devices attached to the stationary means, the wave devices being separated longitudinally from each other and conductively insulated from the conductive devices.

14; In combination, movable members and stationary means, several, wave devices attached to the movable members for cooperating with conductive devices attached to the stationary means, the wave responsive devices being separated longitudinally from each other and conductively insulated from the wave conductive devices whereby Waves produced in one device do not directly affect another like device.

15. In combination, movable members and stationary means, several wave devices attached to the movable members for cooperating with conductive devices attached to the stationary means, the wave responsive devices being separated longitudinally from each other and conductively insulated from the wave conductive devices whereby waves produced in one device do not directly alfect another like device and grounded shields between the devices on the members.

16. In combination, two movable loop antennae, and a stationary loop the characteristics of which are adapted to be varied in accordance with trac conditions in inductive relation thereto, the antennae being so arranged that they will affect each other through the stationary loop only.

17. In a train control system, means for sending Hertzian waves located on a train, and means for receiving the waves located on the train whereby the condition of trali'ic is indicated by the characteristics of the reception had.

18. In a train control system, means or sending Hertzian waves, located on the train, means for receiving Ithe waves on the train., and means for conductively associating the sending and receiving means according to traiiic conditions.

In testimony whereof I hereunto aix my signature.

JOHN HYS HAMMOND, JR.

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